Cloud storage is receiving increasing attention and importance recently. Cloud storage offers their users cost-effective, convenient and highly available storage services. Conventional clouds rely on cost-effective techniques such as data compression and data deduplication in order to save storage costs for the cloud.
Data deduplication clearly comes at odds with data confidentiality. That is, existing semantically secure encryption techniques render any two identical chunks of data indistinguishable to the cloud storage provider, thus preventing the cloud storage provider from effectively deduplicating data.
In the non-patent literature of Pasquale Puzio, Refik Molva, Melek Önen and Sergio Loureira ClouDedup: Secure Deduplicalion with Encrypted Data for Cloud Storage, Proceedings of IEEE CloudCom 2013, A Secure Data Deduplication Scheme for Cloud Storage, Jan Stanek, Alessandro Sorniotti, Elli Androulaki, and Lukas Kenc, Proceedings of Financial Cryptography and Data Security, 2014, Boosting Efficiency and Security in Proof of Ownership for Deduplication, Roberto Di Pietro, Alessandro Sorniotti, Proceedings of ASIACCS 2012, and Mihir Bellare and Sriram Keelveedhi, Thomas Ristenpart, DupLESS: Server-Aided Encryption for Deduplicated Storage, Proceedings of Usenix Security 2013, techniques are disclosed for performing deduplication over encrypted data or for a construction for a proof of ownership to attest that a user indeed possesses a file which is deduplicated by a cloud for example. These conventional techniques do not efficiently protect against malicious users to abuse the system, e.g., upload data encrypted with the wrong encryption key, etc.
However one of the disadvantages is, that these techniques are not transparent for the users of a cloud storage provider. Another disadvantage is, that the users do not have a fine-grained control over their possibly deduplicated files.